1. Field of the Invention
The present invention relates to a rotatable member, particularly to a method for manufacturing a bearing or a shaft having good lubricant retention.
2. Description of Related Art
At present, bearings are widely used in spindle motors in devices, such as compact disc (CD) drivers, digital video disc (DVD) drivers, hard disk drivers, laser beam printers, floppy disk drivers or in heat-dissipation fans. Spindle motors require bearings of small size, high rotational accuracy and long life. A related bearing defines a bearing hole therein. A shaft is rotatably received in the bearing hole. Lubricant is often used between an inner circumferential surface of the bearing and an external circumferential surface of the shaft to reduce abrasion of the bearing and the shaft. However, the lubricant is prone to leak out of the related bearing so that the bearing cannot work normally due to lack of lubricant. Thus, lubricant retention becomes a problem in the related bearing.
It is therefore desirable to provide a bearing having good lubricant retention and a long operating life, and a method for manufacturing the same.